Tube base and socket



Sept. 1, W35. J. HIRMANN TUBE BASE AND SOCKET Filed Aug. '5, 1935 2Sheets-Sheet 1 a l I ATTORNEY I Sept. 17, 1935 J HlRMANN 2,Mi,4 I

TUBE BASE AND SOCKET Filed Aug. 3, 1933 2 ShGQS-SheGt 2 Patented Sept.17, 1935 PATENT OFFICE v TUBE BASE AND SOCKET Julius Hirmann, Hillside,N. J., assignor to Radio Corporation of America, a corporation ofDelaware Application August 3, 1933, Serial No. 683,434

3 Claims.

My invention relates to vacuum tubes and the like, and more particularlyto bases and sockets for such tubes. r r a The conventional vacuum tubehas a cupshaped base with a flat bottom on which tubular contact pinsare mounted in a circle near the rim to project perpendicularly from thebottom of the base, thus adding to the overall length of the tube. Thesetubular contact pins are connected to the electrode elements of the tubeby leading-in wires threaded into and soldered to the pins. Theconventional socket has spring contacts which engage the contact pins ofthe base. The socket contacts extend radially outward andare fastened attheir ends or intermediate their ends to the bottom of the socket byrivetsor the like. Thesocketis inherently large and bulky, and extendsconsiderably beyond the outline of the base of the tube.

Anincrease in the number of contact pins on the base decreases thespacing between the pins, increases the tendency for voltage breakdownthrough the base, and greatlyincreases thedif .ficulty of basing thetube particularly the threading of the leading-in wires into the contactpins. The number of contacts which can be accommodated by theconventional socket has like- ,wise reached a practical limit because oflack of space and because of the increase in the tend- 3Q ency ofvoltage breakdownthrough'the socket. Assembly of the socket due to thenumber of parts required. islikewise mademore difficult.

Not onlyhas the practicallimit been reached in the numberof contactswhich can be mounted in a conventional way intube bases and sockets ofconventional size, but tubejbases and sockets only about one-half theconventional size must be made with as many or. even more contacts thanthe bases and sockets of conventional size.

. The usual number of conventional contact pins "cannot bevmounted in,the conventional way on the smaller base, yet a corresponding reductionin size of the contact pins will result in pins which are too weak forpractical use, which do not have enough contact area and whichofferivery great difiiculty in the threading of the leading-in wiresinto the pins. Furthermore, there is a practical limit in the reductionof the diameter of the contact pins and of the leading-in wires, as the50 wires must be sufficiently large to carry the necessary current andalso stiff enough to thread easily into ,the pins, which must, ofcourse, have a bore somewhat larger than the wire, A reduction, inthesize of the conventional socket andits contactswill result incontacts which sufiicient'contact area, and which increase thedifiiculty of assembling the socket. It would not be practical tomaterially reduce the size of contacts in the socket and still havethese contacts 5 properly cooperate with pins on the tube base whichwere not materially reduced from conventional size.

The conventional contact pin is in effect riveted into the base byupsetting or spinning the 10 inner end of the pin over the inside of thebottom of the base. i The inner end is thus enlarged and in effectincreases the diameter of the pinso that more room is required forspacing between the pins. As it is not feasible to reduce the di- 15ameter of the pins, the space required for fastening the pins to thebase cannot be reduced, nor can smaller contacts be used, as theconventional socket contact is larger than the base pin which 20 itengages. a

,One object of my invention is to provide a base and socket which canbe'made smaller than the conventional base and socket and yet have asmany or even more contacts of ample area and properly spaced so that theelectrical and me- 2 chanical properties of the smaller base and socketare ample to meet all requirements. Another object of, my invention isto provide a base so constructed'that the attachment of the leading-in,wires to the contacts is simple and 30 easier than soldering to tubularcontact pins.

A further object of my invention is to provide a base and socket havingmechanically strong contacts/which are so arranged that more angularspace'is made available for the contacts than in the conventional baseand socket and which are made to occupy less angular space on the baseand socket than the contact pins and V socket contacts commonly used,yet have as great or even greater contact area than the conventional pinand socket contacts.

Still anotherobject of my invention is to provideimproved base andsocket contacts which are simple and inexpensive to make.

These and other objects will appear hereinafter.

i The novel features which I believe to be'characteristic ofmy inventionare set forth with 'particularity in the appended claims, but theinvention itself will be best understood by reference to the followingspecification taken in con- Figure 2 is an enlarged top view of the baseshown in Figure 1 with the bulb removed.

Figure 3 is a longitudinal section of the lower end of the tube shown inFigure 1 taken along the line 33 of Figure 2.

Figure 4 is an enlarged bottom view of the base shown in Figure 1.

Figure 5 is a perspective view of a contact terminal made in accordancewith my invention.

Figure 6 is a perspective view of a socket constructed in accordancewith my invention and.

the tube shown in Figure l which cooperates therewith.

Figure '7 is a top view of the socket shown in Figure 6 with partsbroken away to show details of construction.

Figure 8 is a longitudinal section of the socket shown in Figure 6 takenalong the line 88 of Figure '7.

Figure 9 is a horizontal section of the socket shown in Figure 6 takenalong the line 9-9 of Figure 8.

Figure 10 is a perspective view of a socket contact made in accordancewith my invention.

The vacuum tube shown in Figure 1 of the drawings has an evacuated bulbI enclosing the usual cathode, anode, and grid or grids. The bulb IIIhas secured to it by cement a tubular base preferably molded frominsulating material and comprising a collar provided with the usualindexing pin I2, and a lower portion I3 of smaller outside diameter andsmaller inside diameter than the collar for providing an inside shoulderI4. In the particular device shown in Figures 1, 2, 3, and 4, the baseis provided with apertures I which extend through the base from theinterior of the base at the top of the shoulder M to the exterior of thebase at the lower end of the collar The portion I3 of reduced diameterhas at its lower end slots I6 directly in line with the apertures I5.Flat ribbon contacts extend through the apertures l5 and slots l6 andare wrapped longitudinally around the portion |3 of reduced diameter asshown to provide flat contact faces on the outside of the base. The endsof the ribbon contacts are brought together and welded to fasten thecontacts in place on the base and also to form connecting lugs I8 and I9which facilitate and simplify the connecting of the lead wires 20 to thebase contacts ll.

When the tube is based the connecting lugs I8 and I9 practically adjointhe outer ends of the lead Wires 20, whichextend through the tubularportion I3 of the base shell. The ends of the lead wires are insertedbetween and then welded to the connecting lugs I8 and I9, wherebythreading of the lead wires into tubular contact pins is eliminated, anda good electrical connection made more easily than by soldering. Thecontacts are backed and supported by the base shell I3 and althoughnarrow are held sufliciently rigid to constitute a strong rigid contact.

As the width of the ribbon contact may be less than the diameter of theconventional tubular contact, and since the ribbon contacts are spacedaround the exterior of the base instead of in a circle on the bottom ofthe base near the rim, as is done with tubular contacts, more of suchcontacts may be accommodated on a base of the usual size, or the size ofthe base can be materially reduced and still the maximum number ofcontacts now feasible for the usual size base can be used. The flatcontacts have ample contact area, at least as much as the conventionalcontact, and because of their being mount- 4 ed on the side of the basethe tube is shortened and less head room required for it.

The flat contacts I i may to advantage be made 5 of nickel which iseasily worked and welded. They may be made in various ways, but I preferto cut them from metal ribbon and form them automatically by machine, asit is easier to shape the metal ribbon into a flat contact than it is tomake the usual type of tubular contact.

It is obvious that the base can be registered with the socket in variousways; for example, by placing the contacts nonsymmetrioally around theshell or providing studs or projections on the base shell to entercorresponding slots in the socket. I prefer to register the base andsocket by means of a stud or pin I2 for this purpose.

A socket for the vacuum tube with the base shown in Figures 1 to 4inclusive is shown in Figures 6 to 9 inclusive. It comprises separateupper and lower parts which telescope and between which the socketcontacts are clamped. The tubular upper part 29 of the socket has acentral opening 3|! large enough to receive the tube base H and has inone side an indexing slot 3| for the stud or pin l2 on the base of thetube. This upper part 29 has a flange 32 with bosses 33 for attachingthe socket to a panel, and a shoulder 34 on the interior wall forlimiting the extent to which the base may be inserted in the socket.

When the base is home in thesocket the base contacts I! are in registrywith slots35 in the lower end of the part 29 of the socket as mostclearly shown in Figures 8 and 9. Spring contacts 3! project throughthese slots and have flat portions 38 which are resiliently forced intoengagement with the base contacts by spring portions 39. Connections tothe contacts are 40 made by connecting lugs 40 on the socket contacts.

The contacts 31 are held in place by being clamped between the upperpart 29 grooved to receive the contacts and the lower cup-shaped part 4|of the socket, which has a lip 42 to cooperate with the flange 32 of theupper part. The two parts of the socket are riveted together by rivets43. The bottom of the lower cup-shaped part 4| has on the inside anannular channel 44 in which the lower ends of the contact springs rest,and by which the extent of inward movement of the spring contact islimited. Apertures 45 in the bottom of the socket permit particles ofdirt and the like to fall out of the socket through the bottom. Anannular collar 46 at the center of the bottom part 4| prevents foreignobjects dropping into the socket far enough to short circuit thecontacts 31. 0

It will be obvious that when the base is in- 6 serted in the socket, thebase contacts I! will engage the flat part 38 of the socket contacts 31and make a good contact of ample area. The wiping action between thecontacts as the base is inserted in the socket insures clean contactsurfaces, and the spring 39 of the socket contact insures sufficientpressure between the contacts. The socket contacts 31 for a socketconstructed in accordance with my invention can be made in s much thesame way as the base contacts I1. I

It will be seen that I have provided a base and socket in which themaximum number of contacts which it is now feasible to use for theconventionalbase and socket can be materially increased and still havethe base and socket fully means of my invention I providesimple-contacts which can be manufactured cheaply and easily from metalribbon for both the base and socket. [The embodiment of the inventionillustrated and described herein has been selected for the purpose ofsetting forth the principles involved, but it will be apparent thatvarious modifications may be made to meet the different. conditionsencountered in use and I, therefore, intend to cover all modificationswithin the scope of the appended claims.

What is claimed as new is,--- V 1. A vacuum tube base including atubular member having at one end a collar of larger diameter than therest of the member and spaced slots in the other end, said tubularmember having apertures spaced around its periphery intermediate itsends and in line with said slots, and ribbon contacts extended throughsaid apertures and said slots and longitudinally wrapped around saidbase between said apertures and said slots to provide fiat contactsurfaces and to space said contacts around said tubular member, each ofsaid contacts having its ends fastened together to secure the contact tosaid tubular member and to provide lugs between which a lead wire isattached to the contact.

2. A vacuum tube base including a tubular 5 member having aperturesspaced around its periphery intermediate its ends and spaced slots inone end in line with said apertures and U-shaped ribbon contactsextended through said apertures and said slots and longitudinallyWrapped around said tubular member between said apertures and said slotsto provide external fiat contact surfaces and to space said contactsaround said tubular member, each of said contacts having its endsfastened together adjacent the slots to secure the contact to saidtubular member and to provide lugs at the inner surface'of the tubularmember to which a leadwire is attached.

3. A vacuum tube base including a tubular member having a shoulder onthe interior thereof, said member having spaced apertures extendingthrough said member at said shoulder and having slots in one end thereofin line with said apertures, and U-shaped ribbon contacts extendedthrough said apertures over said shoulder and wrapped around said memberto lie fiat against said member with the ends of said contacts extendedthrough and fastened together adjacent said slots to secure saidcontacts in position around said member and to provide lugs at the innersurface of said tubular member.

JULIUS HIRMAN N.

